1. Field of the Invention
The present invention relates to an image processing system, and in particular, to a video format mode detector which detects the format mode of a video signal transmitted from an image data output device.
2. Description of the Related Art
With rapid spread of computer in the age of information and multimedia, personal computers become the necessities of life. Since the personal computer serves as a multimedia, there has been efforts to display images required for internet, PC communications, video conference, games, and education programs such as movies using the personal computer on a larger picture effectively and vividly. This requires, first of all, a display device having larger picture, for example, television receiver (referred to as TV hereinafter) or screen. A large-sized TV is frequently used because the screen has low brightness and resolution. This produces a problem that TV is fixed in NTSC or PAL mode while the format mode of a video signal transmitted from the personal computer is one of various modes such as VGA, SVGA and XGA.
Meanwhile, employing a separate display requires a device for connecting the display to the personal computer. Furthermore, the device for connection is required to adjust the output resolution of the personal computer to meet the resolution of the display. However, due to the various format modes of the video signals transmitted from the personal computer, it is difficult to design the device for converting the format of the video signal received from the computer according to the resolution of the display connected to the device. Accordingly, a wide variety of methods and devices have been contemplated for controlling a video display device to display video signals of different formats as exemplified by the following references, incorporated herein by reference: U.S. Pat. No. 5,790,096 to Jacques R. Hill, Jr. entitled Automated Flat Panel Display Control System For Accommodating Broad Range Of Video Types And Formats; U.S. Pat. No. 5,825,435 to Leendert Vriens et al. entitled Color Cathode Ray Tube And display Device; U.S. Pat. No. 5,838,381 to Yasuhiro Kasahara et al. entitled Image Display Apparatus Capable Of Displaying Personal Computer Signals And Television Signal By Conversion Into A Signal Of A Higher Number Of Pixels; U.S. Pat. No. 4,991,023 to Gary H. Nicols entitled Microprocessor Controlled Universal Video Monitor; U.S. Pat. No. 5,404,153 to Manbok Kim entitled Super VGA Monitor Interface Circuit; and U.S. Pat. No. 5,694,175 to Frederic Gaigneux et al. entitled Method For Recognition Of Video Standards And Circuit For Implementing This Method.
Accordingly, we have determined that there is a need for a video format mode detector which is able to automatically detect various format modes of video signals output from the personal computer.